Aircraft fuel and hydraulic systems include a large number of couplings or fittings which interconnect various components within the fuel and hydraulic systems. The couplings must be easy to connect and must provide a locking arrangement to prevent inadvertent uncoupling. It is advantageous to provide couplings or fittings which are of minimum weight, simple in construction, and are also easily serviced for routine maintenance and repair.
The owner of the current invention is also the owner of a number of previous patents for positive lock couplings which are used to interconnect confronting ends of fluid carrying conduits in an aircraft. These patents include the U.S. Pat. Nos. 5,871,239; 6,050,609; and 6,073,973. Each of these patents are hereby incorporated by reference in their entirety. Characteristics common to each of the inventions disclosed in these patents are coupling devices which include a plurality of threaded members which are rotatable in a locking direction, and rotatable in an opposite unlocking direction. Positive locking of the couplings is achieved by positive locking features in the form of locking tabs which are received in corresponding notches/reliefs. A resilient member is provided to ensure that the couplings remain in a locked position when the coupling is tightened to a predetermined extent during rotation in a locking direction. Visual indicia is provided to indicate when the couplings have been placed into locking engagement.
Nadsady U.S. Pat. No. 3,669,472; Gale et al. U.S. Pat. No. 4,808,117 and Gale et al. U.S. Pat. No. 4,928,202 each disclose a coupling device in which the tightening of the coupling parts is readily accomplished, but accidental loosening is restrained by spring fingers carried by one of the coupling parts which engage indentations or notches on the other coupling part in such a manner as to favor relative rotation of the coupling parts in the tightening direction, while restraining with greater force the rotation of the coupling parts in the opposite unlocking direction.
Cannon U.S. Pat. No. 3,999,825; Filippi U.S. Pat. No. 4,008,937; Mahoff U.S. Pat. No. 4,249,786 and Gale U.S. Pat. No. 4,346,428 each disclose a coupling with one or more toggle latches which snap into a positive locking position.
Spinner U.S. Pat. No. 4,285,564 discloses a coaxial plug connector wherein a first ring of axially pointed teeth is provided around the circumference of a cap ring. A first connector has a ring with teeth for engaging the teeth on the cap ring. The cap ring is withdrawn axially against the force of a biasing spring when the coupling is rotated to a different position. The cap ring is released and the spring urges it into locking engagement with the tooth ring. Thus, accidental rotation of the cap ring relative to the first connector is prevented.
Runkles et al. U.S. Pat. No. 4,881,760 discloses a coupling with locking tines having visible indicia for determining whether or not the tines are in locked position.
Runkles et al. U.S. Pat. No. 4,900,070 discloses a coupling with spring biased rotatable locking tines.
Although each of the prior art references may be suitable for their intended purposes, there are a number of additional objectives which are met by the present invention based upon the particular structure in which the fitting assembly is incorporated.
More particularly, the present invention provides a solution for interconnecting two adjacent modular structures. For example, one method that can be used in the construction of an aircraft is the use of separate modular structures which are assembled to form the finished aircraft. Different manufacturing entities may be responsible for producing various modular assemblies or components. Because each of the assemblies or components may be manufactured at remote locations, in order to minimize the efforts required to assemble the components for the finished aircraft, the various components must be designed so that there is minimal construction effort required to mate the components.
One particularly challenging problem arises for interconnection of fluid carrying members between the various modular components of the aircraft. For example, a fuel tank may span between both the fuselage and wing of an aircraft. In such a case, the mating of the modular components, that is, the wing and the fuselage, must be adapted so that a leak proof connection is provided between the modular components. Additionally, because of the various specified manufacturing tolerances of the aircraft components, the fluid connection must also take into account these tolerances so that the connection can remain leak proof despite misaligned modular components.
Another consideration in providing a leak proof connection between the modular components is that the hardware used to span between the modular components must accommodate both parallel match mate and perpendicular or guillotine type match mate assembly methods. A parallel match mate assembly involves two modular components of the aircraft which are joined to one another by movement of the modular components toward one another in a substantially common plane until the abutting ends of the components are aligned. A perpendicular or guillotine type match mate assembly method involves movement of the modular components with respect to one another in a perpendicular or transverse fashion until the abutting ends of the components are aligned.
Yet another consideration in joining a pair of modular components is the need to minimize or eliminate satellite holes placed in the modular component themselves to assist in stabilizing or attaching the hardware for connecting the modular components. In other words, it is desirable to eliminate additional holes or other structural modifications to the modular components which may otherwise alter certain strength characteristics of the modular components, or may introduce vibrational concerns or other structural issues.
Yet another consideration in providing a connection between the modular components is to create redundant sealing at all leak paths, thereby further enhancing the connection's ability to provide a leak proof path during all types of operating conditions.
Yet other considerations include ensuring that the hardware is positively locked to the modular components, and to ensure electrical conductivity through the entire fitting assembly to prevent static buildup across the connection.
With the fitting assembly of the present invention, each of the requirements and considerations set forth above are addressed with a fitting assembly that is structurally simple, can be installed and maintained with minimal effort, and has numerous other advantages as set forth below with respect to the drawings and the description of the invention.